JP2003274585A - Concentrated coil dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concentrated coil DC motor, wherein the adverse effects of the magnetic flux from the stator are eliminated, and further, problems associated with the reduction in rotor inertia are solved. <P>SOLUTION: The concentrated coil DC motor 1 comprises the stator 3 on which coils are wound by concentrated winding, and a rotor 2 with magnets built therein which is rotated in the stator 3. Magnetic flux shield holes 21 are formed in a core portion 9 between the magnetic poles 19 of the rotor 2. Further, the maximum thickness of the core portion 9 between the magnetic flux shielding holes 21, and the circumferential surface of the rotor 2 is controlled to 3% or higher of the diameter of the rotor 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentrated winding DC motor including a stator having a coil wound in a concentrated winding system and a rotor having a built-in magnet.

[0002]

2. Description of the Related Art Conventionally, a compressor that constitutes a refrigerant circuit of an air conditioner or a cooling device is required to be downsized and energy efficiency is improved. Therefore, a motor used for the compressor is also small and has high output. Has been developed. In this case, a distributed winding type brushless DC motor has been conventionally used as a general compressor motor, but in recent years, a concentrated winding type brushless DC motor has been proposed which can achieve simplification of the manufacturing process, downsizing, and efficiency improvement. ing.

That is, a conventional concentrated winding type brushless DC
The motor is composed of a stator and a rotor, and the stator is composed of a core portion in which electromagnetic steel plates (silicon steel plates) are laminated and a coil. The core portion is provided with a tooth portion, the tooth portion has a predetermined width, and the tooth tip ends are provided on both sides of the tooth portion along the surface of the rotor. The coil is directly wound around the tooth portion using the space of the slot portion, and the magnetic pole of the stator is formed by the concentrated direct winding method.

On the other hand, the rotor had a shape as shown in FIG. That is, the rotor 101 also has the core portion 102 formed by laminating electromagnetic steel plates (silicon steel plates). This core part 1
Four cutouts 103 are formed on the outer periphery of 02.
Between these notches 103 ... Salient pole-shaped magnetic poles 104 ...
・ 4 places are formed, and each magnetic pole 104 has a slot 1
No. 06 is formed, and the permanent magnet 107 is formed in each slot 106.
Is embedded.

The permanent magnet 107 may be an ordinary ferrite magnet, but in order to downsize the motor, B is used.
A magnet having a large H product, that is, a so-called rare earth magnet such as a neodymium magnet made of neodymium, iron, or boron, or a samarium cobalt magnet is used.

[0006]

Here, when the above-mentioned notch (FIG. 7) is not formed as shown in FIG. 8, noise increases due to the magnetic flux flowing from the stator. In addition, a magnetic short circuit occurs between the magnetic poles of the rotor, which lowers the motor identification. Therefore, in FIG. 6, a notch is formed between the magnetic poles to form a gap for shielding the magnetic flux from the stator. However, since the weight of the core portion is reduced by the amount of the notch, the inertia (inertia) of the rotor is reduced. .

On the other hand, when a concentrated-winding DC motor is used in a compressor such as a single-cylinder rotary compressor or reciprocating compressor, the magnitude of torque fluctuation becomes a problem, but a notch is formed in the rotor core as shown in FIG. Then, when the inertia becomes small, there is a problem that it is not possible to suppress the rotation unevenness in the compression portion of the compressor and the vibration increases.

Further, when the slot 106 and the permanent magnet 107 are enlarged and the magnet interval is narrowed as shown in FIG. 9 without forming such a notch, the magnetic flux cannot be effectively utilized with respect to the amount of magnet used this time. There was a problem.

The present invention has been made to solve the above-mentioned conventional technical problems, and eliminates the adverse effect of magnetic flux from the stator while solving the problems associated with the reduction of the rotor inertia. The purpose is to provide a motor.

[0010]

According to a first aspect of the present invention, there is provided a concentrated winding DC motor comprising a stator having a coil wound in a concentrated winding system and a rotor having a built-in magnet rotating in the stator. A magnetic flux shielding hole is formed in the core portion between the magnetic poles of the rotor, and the maximum value of the core portion thickness between the magnetic flux shielding hole and the outer circumference of the rotor is set to 3% or more of the rotor diameter. While eliminating or suppressing the adverse effect due to the wraparound of the magnetic flux, it is possible to increase the rotor inertia as compared with the case where the notch is formed as in the conventional case.

As a result, the rotation can be smoothed even with a load having a large torque fluctuation, and the vibration and noise can be reduced.

According to the invention of claim 2, in addition to the above, the minimum value of the core thickness between the magnetic flux shielding hole and the outer circumference of the rotor is 0.35.
Since it is less than or equal to mm, the magnetic short circuit between the magnetic poles of the rotor can be reduced as much as possible. This makes it possible to prevent deterioration of the motor characteristics, and
Since the abnormal rotor magnetomotive force distribution can be prevented, the rotor position detection signal can be stably obtained.

According to the invention of claim 3, in addition to the above-mentioned inventions, a magnetic short-circuit prevention groove extending in the radial direction of the rotor is formed in the core portion between the magnetic flux shielding hole and the outer circumference of the rotor. The groove makes it possible to prevent the deterioration of the specific motor due to the magnetic short circuit of the magnetic flux of the stator.

According to another aspect of the present invention, in a concentrated winding DC motor including a stator having a coil wound in a concentrated winding system and a rotor with a built-in magnet rotating in the stator, a core between magnetic poles of the rotor is provided. A protrusion protruding toward the outer peripheral side is formed in the portion, and the rotor diameter in the protrusion is smaller than the rotor diameter in the magnetic pole so that the gap size between the stators in the protrusion is more than twice the gap size in the magnetic pole. Therefore, the gap between the stators in the protruding portions makes it difficult for the magnetic flux from the stator to pass through, and eliminates or suppresses the adverse effect due to wraparound,
Due to the presence of the protruding portion, it is possible to increase the rotor inertia as compared with the case where the notch is formed as in the conventional case.

As a result, similar to the above, it becomes possible to achieve smooth rotation even for a load with large torque fluctuations and to reduce vibration and noise. Further, since the magnetic short circuit between the rotor magnetic poles can be prevented or suppressed by eliminating the bridge on the outer peripheral portion of the magnet, it is possible to prevent the deterioration of the motor characteristics and also prevent the abnormal rotor magnetomotive force distribution. Therefore, the rotor position detection signal can be stably obtained.

According to the invention of claim 5, in addition to the above-mentioned inventions, since the cut portion is formed on the magnetic pole outer peripheral portion of the portion located in the rotational direction of the rotor, the iron loss at high rotation is reduced and the efficiency is improved. It will be possible to plan.

According to the invention of claim 6, in addition to the above inventions, the magnetic pole angle of the rotor is set to 55 degrees or more and 70 degrees or less.
The magnetic flux of the magnet can be effectively used to improve the torque and the torque fluctuation.

According to the invention of claim 7, in addition to each of the above inventions, since the cut portion is formed in the inner diameter side tooth portion up to the opening except the tooth portion of the stator, the high frequency component is reduced and the torque waveform is smoothed. Thus, it is possible to reduce the fluctuation of the torque and reduce the vibration when the motor rotates.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view (excluding coils) of a concentrated winding brushless DC motor 1 of an embodiment to which the present invention is applied, and FIG. 2 is a sectional view taken along the line AA of FIG. The motor 1 of the embodiment is, for example, a concentrated winding type brushless DC motor used as a drive motor of a single-cylinder rotary compressor or reciprocating compressor that constitutes a refrigerant circuit of an air conditioner or a cooling device, and includes a stator 3 and this stator 3. And a rotor 2 that rotates inside.

The stator 3 is composed of a core portion 4 formed by laminating electromagnetic steel sheets (silicon steel sheets) and a stator coil (not shown) wound around the core portion 4. Core part 4
Is provided with a tooth portion 6 having a predetermined width, and the tip of this tooth portion 6 is extended to both sides to form a tooth portion tip portion 7 along the surface of the rotor 2. Then, a stator coil (not shown) is directly wound around the tooth portion 6 using the space of the slot portion 8 to form the magnetic pole of the stator 3 by the concentrated series winding method.

As shown in FIG. 1, a part P1 and P2 of the tooth tip portion 7 is cut and removed (in the figure, P1 and P2 are shown one by one, but all tooth tip portions 7 are shown). Part 7 is similarly cut). The cut portion is only the tooth tip 7 in the direction in which the rotor 2 rotates, for example, P1.
Although one side is sufficient, the other end P2 of the tooth tip portion 7 is also cut so that the rotor 2 can be inserted from either direction of the stator 3 when the motor is assembled. In this way, even if the tooth tip portions 7 on both sides are cut, the influence on the torque characteristics of the motor is negligible.

With this configuration, the distance from the rotor 2 does not become evenly spaced along the outer peripheral surface of the rotor 2, so that the distance from the rotor 2 is cut off at the tooth tip portion 7. By increasing the magnetic resistance, the magnetic resistance in the cut portion increases, and the magnetic flux is averaged without concentration at the tooth tip 7 in the direction in which the rotor 2 rotates.

Without this cut, the peak value of the force acting on the center side of the core portion 9 (described later) of the rotor 2 of the motor 1 becomes large, the width of the change in the force also becomes large, and the temporal fluctuation rate becomes large. Increases, which causes vibration of the motor. On the other hand, when there is a cut as in the present invention, since the peak value does not become large and becomes a comparatively gentle curve, the width of change in force is small and the temporal fluctuation rate is also small.
Vibration of the motor 1 can be suppressed.

As a result, the relationship between the rotor rotation angle and the torque of the motor 1 becomes a smooth waveform with less harmonic components, the fluctuation of the torque can be reduced, and the vibration during the rotation of the motor 1 can be reduced. .

On the other hand, the rotor 2 has a core portion 9 formed by laminating similar electromagnetic steel sheets (silicon steel sheets) and permanent magnets 12 embedded in slots 11 formed in the core portion 9. ..And end plates 13 and 14 made of non-magnetic material
The balance weight 16 and the oil separating plate 17 are integrated by a rivet 18 (FIG. 2).

FIG. 3 shows the end plates 13 and 14 of the rotor 2.
The plan view is shown with the balance weight 16 and the oil separating plate 17 removed. The slot 11 ... is the rotor 2
4 are formed in the peripheral portion of the core portion 9, and the permanent magnets 12 are inserted and embedded in the respective slots 11 ..., By this, magnetic poles 19 ... Are formed in 4 places.

In this case, the angle of each magnetic pole 19 is 55 degrees or more and 70 degrees or less. If the angle of the magnetic pole is too large, the magnetic flux of the permanent magnet 12 cannot be used effectively,
Although the torque is decreased and the torque fluctuation is increased, the magnetic flux angle of 55 degrees or more and 70 degrees or less is used to effectively use the magnetic flux of the permanent magnet 12 to improve the torque and the torque fluctuation. Will be able to.

The permanent magnet 12 may be an ordinary ferrite magnet, but in order to downsize the motor, BH is used.
A so-called rare earth magnet such as a magnet having a large product, that is, a neodymium magnet made of neodymium, iron, or boron, or a samarium cobalt magnet is used.

Further, magnetic flux shielding holes 21 are respectively formed (four places in total) in the core portion 9 between the magnetic poles 19, 19. This magnetic flux shielding hole 21 is provided with permanent magnets 12, 12 on both sides.
The side is close to the outer peripheral surface of the rotor 2 and the slot 11, and the central portion has a shape located inside the rotor 2. That is, the thickness of the core portion 9 between the magnetic flux shielding hole 21 and the outer peripheral surface of the rotor 2 has the maximum value in the central portion, and the thickness of the core portion 9 in this portion (P3 in FIG. 3) is 3% of the diameter of the rotor 2. That is all. Further, the thickness of the core portion 9 between the magnetic flux shielding hole 21 and the outer peripheral surface of the rotor 2 has a minimum value on both sides, and the thickness of the core portion 9 in this portion (P4 in FIG. 3) is set to 0.35 mm or less. .

Thus, the magnetic flux shielding hole 21 is formed in the core portion 9 between the magnetic poles 19 of the rotor 2 and
By setting the maximum value of the thickness of the core portion 9 between the magnetic flux shielding hole 21 and the outer peripheral surface of the rotor 2 to 3% or more of the diameter of the rotor 2, the magnetic flux shielding hole 21 serves as a gap.
It is difficult for the magnetic flux from to wrap around. This eliminates or suppresses the adverse effects of magnetic flux wraparound,
Compared with the conventional case where a notch is formed, the magnetic flux shielding hole 2
It is possible to increase the inertia of the rotor 2 by the weight of the core portion 9 between the outer peripheral surface of the rotor 1 and the outer peripheral surface of the rotor 2.

Therefore, even when the compressor is used in a compressor such as a single-cylinder rotary compressor or a reciprocating compressor, which has a large torque fluctuation, it is possible to realize smooth rotation and reduce vibration and noise. Like

Further, since the minimum thickness of the core portion 9 between the magnetic flux shielding hole 21 and the outer peripheral surface of the rotor 2 is 0.35 mm or less, the magnetic short circuit between the magnetic poles 19 of the rotor 2 is reduced as much as possible. Will be able to. This makes it possible to prevent the characteristics of the motor 1 from deteriorating and also prevent abnormal rotor magnetomotive force distribution, so that the rotor position detection signal can be stably obtained.

Next, FIG. 4 shows a plan view of another embodiment of the rotor 2 of the motor 1 according to the present invention. In this case, the magnetic pole 1 of the portion located in the rotation direction of the rotor 2 in FIG.
Arc-shaped or linear cut portions 26 are formed on the outer peripheral portions of 9 ...

As described above, by forming the cut portion 26 on the outer peripheral portion of the magnetic poles 19 ... In the portion located in the rotational direction of the rotor 2, the iron loss during high rotation of the motor 1 is reduced and the efficiency is improved. You will be able to improve.

Next, FIG. 5 shows a plan view of another embodiment of the rotor 2 of the motor 1 according to the present invention.
In this case, the magnetic flux shielding holes 21 ...
In the core portion 9 between the outer peripheral surface of the rotor 2 and the outer peripheral surface of the rotor 2, magnetic short circuit prevention grooves 27 extending in the radial direction of the rotor 2 are formed.

Thus, by forming the magnetic short circuit prevention groove 27 extending in the radial direction of the rotor 2 in the core portion 9 between the magnetic flux shielding hole 21 and the outer peripheral surface of the rotor 2, the stator 3 is formed.
It is also possible to prevent a specific drop in the motor due to the magnetic short circuit of the magnetic flux.

Next, FIG. 6 shows another motor 1 of the present invention.
2 shows a plan view of the rotor 2 of FIG. Also in this case, the rotor 2 has a core portion 9 formed by laminating similar electromagnetic steel sheets (silicon steel sheets), and a slot 11 formed in the core portion 9.
..... Permanent magnets 12 embedded in ..., End face plates 13 and 14 made of a non-magnetic material, balance weights 16 and oil separating plates 17, which are rivets 18
It is assumed that they are integrated and configured.

Similarly, FIG. 6 is a plan view of the rotor 2 excluding the end plates 13 and 14, the balance weight 16 and the oil separating plate 17. Similarly, the slots 11 ... Are formed at four locations around the core portion 9 of the rotor 2, and the permanent magnets 12 are inserted and buried in the respective slots 11 ..., whereby the magnetic poles 19 ... Are formed in four places.

Also in this case, the angle of each magnetic pole 19 is set to 55 degrees or more and 70 degrees or less, and the permanent magnet 12 is also embedded. And in this case, each magnetic pole 1
The protrusions 31 are respectively provided on the core portion 9 between 9 and 19 (total of 4
Are formed). The protrusions 31 are formed by cutting the core portions 9 on both sides of the permanent magnets 12, 12 inward from the outer peripheral surface.

Further, the rotor 2 in the protruding portions 31 ...
Is smaller than the diameter of the rotor 2 at the magnetic pole 19, and the radius is reduced by T as shown in FIG. As a result, the gap size between the rotor 2 and the stator 3 in the protruding portions 31 ... Is twice or more the gap size in the magnetic pole 19.

With this structure, the protrusion 31
.. due to the gap between the stators 3 at
Since it becomes difficult for the magnetic flux from the magnetic flux to pass through, it is possible to eliminate or suppress the adverse effect due to the wraparound of the magnetic flux from the stator 3. On the other hand, as compared with the conventional case where the notch is formed due to the presence of the protrusions 31, ...
It is possible to increase the inertia of the.

As a result, similar to the above, when driving the compressor of the compressor with large torque fluctuations, smooth rotation can be achieved and vibration and noise can be reduced. Moreover, since the bridge on the outer peripheral portion of the permanent magnet 12 is eliminated (the portion indicated by the dimension T in FIG. 6), magnetic short circuit between the magnetic poles of the rotor 2 can be prevented or suppressed. Therefore, it is possible to prevent the characteristics of the motor 1 from being deteriorated, and it is also possible to prevent an abnormal rotor magnetomotive force distribution, so that similarly, the rotor position detection signal can be stably obtained.

[0043]

As described in detail above, according to the first aspect of the invention, the concentrated winding DC is composed of a stator in which a coil is wound in a concentrated winding system, and a rotor with a built-in magnet rotating in the stator. In the motor, a magnetic flux shielding hole is formed in the core portion between the magnetic poles of the rotor, and the maximum value of the core portion thickness between the magnetic flux shielding hole and the outer circumference of the rotor is 3% of the rotor diameter.
As described above, while eliminating or suppressing the adverse effect due to the wraparound of the magnetic flux from the stator in the magnetic flux shielding hole,
It is possible to increase the rotor inertia as compared with the conventional case where the notch is formed.

As a result, the rotation can be smoothed even with a load having a large torque fluctuation, and the vibration and noise can be reduced.

According to the invention of claim 2, in addition to the above, the minimum value of the thickness of the core portion between the magnetic flux shielding hole and the outer circumference of the rotor is 0.
Since the length is 35 mm or less, the magnetic short circuit between the magnetic poles of the rotor can be reduced as much as possible. As a result, it is possible to prevent deterioration of the characteristics of the motor and also prevent abnormal rotor magnetomotive force distribution, so that the rotor position detection signal can also be stably obtained.

According to the invention of claim 3, in addition to the above-mentioned inventions, the magnetic short circuit preventing groove extending in the radial direction of the rotor is formed in the core portion between the magnetic flux shielding hole and the rotor outer periphery.
The magnetic short-circuit preventing groove can prevent the magnetic flux of the stator from being magnetically short-circuited even when the motor is lowered.

Further, according to the invention of claim 4, in the concentrated winding type DC motor comprising the stator in which the coil is wound by the concentrated winding method and the rotor having the built-in magnet rotating in the stator, A protrusion protruding outward is formed in the core between the magnetic poles, and the rotor diameter of the protrusion is smaller than the rotor diameter of the magnetic poles.
Since the gap size between the stators in the protrusions is twice or more the gap size in the magnetic poles, the gap between the stators in the protrusions makes it difficult for the magnetic flux from the stator to pass through and eliminates or suppresses the adverse effects of wraparound, Due to the presence of the protruding portion, it is possible to increase the rotor inertia as compared with the case where the notch is formed as in the conventional case.

As a result, it becomes possible to smooth the rotation and reduce the vibration and noise even for a load having large torque fluctuations as described above. Further, since the magnetic short circuit between the rotor magnetic poles can be prevented or suppressed by eliminating the bridge on the outer peripheral portion of the magnet, it is possible to prevent the deterioration of the motor characteristics and also prevent the abnormal rotor magnetomotive force distribution. Therefore, the rotor position detection signal can be stably obtained.

According to the invention of claim 5, in addition to the above-mentioned inventions, since the cut portion is formed on the magnetic pole outer peripheral portion of the portion located in the rotational direction of the rotor, the iron loss at high rotation is reduced and the efficiency is improved. It will be possible to plan.

According to the invention of claim 6, in addition to the above inventions, the magnetic pole angle of the rotor is 55 degrees or more and 70 degrees or less.
The magnetic flux of the magnet can be effectively used to improve the torque and the torque fluctuation.

According to the invention of claim 7, in addition to the above-mentioned inventions, since the cut portion is formed in the inner diameter side tooth portion up to the opening except the tooth portion of the stator, the high frequency component is reduced and the torque waveform is smoothed. Thus, it is possible to reduce the fluctuation of the torque and reduce the vibration when the motor rotates.

[Brief description of drawings]

FIG. 1 is a plan view of a concentrated winding brushless DC motor according to an embodiment of the present invention.

2 is a cross-sectional view of the motor of FIG. 1 taken along the line AOA.

FIG. 3 is a plan view of a rotor of the motor shown in FIG.

FIG. 4 is a plan view of another embodiment of the rotor of the motor shown in FIG.

5 is a plan view of another embodiment of the rotor of the motor shown in FIG.

FIG. 6 is a plan view of the rotor of another motor of the present invention.

FIG. 7 is a plan view of a rotor of a conventional motor.

FIG. 8 is a plan view of a rotor of another conventional motor.

FIG. 9 is a plan view of a rotor of another conventional motor.

[Explanation of symbols]

1 motor 2 rotor 3 stator 4 core part 6 teeth 7 Tooth tip 9 Core part 11 slots 12 permanent magnet 19 magnetic poles 21 Magnetic flux shielding hole 26 Cut section 27 Magnetic short circuit prevention groove 31 Projection P1, P2 cut part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshito Yakushima             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Keijiro Igarashi             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5H002 AA01 AA09 AB01 AB08 AE07                       AE08                 5H019 AA02 AA06 CC03 CC06 CC08                       DD01 EE01                 5H621 AA02 AA04 GA01 GA04 GA11                       HH01 JK10 PP10                 5H622 AA02 AA03 CA02 CA05 CA10                       CA13 CB03 CB06 PP07 PP11

Claims (7)

[Claims] 1. A concentrated winding type DC motor comprising a stator having a coil wound in a concentrated winding system and a rotor with a built-in magnet rotating in the stator, wherein a magnetic flux is shielded in a core portion between magnetic poles of the rotor. A concentrated winding type DC motor characterized in that a hole is formed and a maximum value of a core portion thickness between the magnetic flux shielding hole and the outer circumference of the rotor is set to 3% or more of a rotor diameter. 2. The concentrated winding DC motor according to claim 1, wherein the minimum value of the core thickness between the magnetic flux shielding hole and the outer circumference of the rotor is 0.35 mm or less. 3. The concentrated winding type according to claim 1 or 2, wherein a magnetic short circuit preventing groove extending in a radial direction of the rotor is formed in a core portion between the magnetic flux shielding hole and the outer circumference of the rotor. DC motor. 4. A concentrated winding DC motor comprising a stator having a coil wound in a concentrated winding system and a rotor with a built-in magnet rotating in the stator, wherein a core portion between magnetic poles of the rotor has an outer peripheral side. The rotor diameter in the protrusion is smaller than the rotor diameter in the magnetic pole, and the gap size between the stators in the protrusion is at least twice the gap size in the magnetic pole. Concentrated winding DC motor characterized by: 5. The concentrated winding DC of claim 1, claim 2, claim 3, or claim 4, wherein a cut portion is formed on a magnetic pole outer peripheral portion of a portion located in the rotation direction of the rotor.
motor. 6. The magnetic pole angle of the rotor is 55 degrees or more and 70 degrees or more.
The concentrated winding DC motor according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the DC motor is set to a value not more than 100 degrees. 7. The cut portion is formed in the tooth portion on the inner diameter side up to the opening portion excluding the tooth portion of the stator, as claimed in claim 1, claim 2, claim 3, claim 4, claim 4. The concentrated winding DC motor according to claim 5 or claim 6.